Fluid control systems for controlling flow of hydraulic or pneumatic fluid have been used in automated manufacturing equipment, production lines and numerous industrial applications. Many of these fluid control systems take the form of a valve manifold that has a series of manifold members assembled together. Each manifold member commonly includes a manifold valve block and a control valve mounted thereon. The control valve may have a solenoid that actuates the valve and has a spring return for moving the valve when the solenoid is deactuated. Other control valves use a double (or dual) solenoid valve that has a first solenoid when actuated that moves the valve to the on position and a second solenoid when actuated that moves the valve to the off position.
Each manifold block houses a circuit board which has circuitry printed thereon to allow actuation of the control valve mounted to the manifold block. The circuit board also has circuits printed thereon to carry voltage to other circuit boards for the other control valves mounted on other manifold blocks.
The number of circuit boards connected together are usually limited by either the capacity of the driver in the communication module or the inherent design of the individual circuit boards. However, an expansion module with its own driver can be placed at the end of the first series of circuit boards to drive a second series of circuit boards and control valve thereby increasing the capacity of the valve manifold.
What is needed is a single line system between a driver and a slave device that provides information and control in the form of power therebetween that can be used for smart slave devices or other slave devices. In particular, it is desired that a circuit board passing through a manifold block has a serial or single communication line for each respective control valve and/or supplementary control, programming or parameterization. With the advent of smart slave devices, for example solenoid valves, proportional devices or pressure switches, it is desirable to transfer sensing data and control signals between a driver and a slave device.
What is also needed is a single control line through the first series of circuit boards that controls a second driver to control at least one proportional valve and other field devices by providing a variable output based on the variable input voltage.